The present invention relates to organosilicon compounds, a process for their production, as well as their use.
Polysulfane-alkyltrialkoxysilanes, such as for example bis[3-triethoxysilylpropyl]tetrasulfane or bis[3-triethoxysilylpropyl]disulfane, and mercaptoalkyltrialkoxy-silanes, such as for example 3-mercaptopropyltrimethoxy-silane or 3-mercaptopropyltriethoxysilane, are used as coupling agents between inorganic materials, for example glass fibres, metals or oxidic fillers, and organic polymers, for example thermosetting materials, thermoplastic materials and elastomers (Angew. Chem. 98, (1986) 237-253).
These coupling agents/bonding agents form stable, chemical bonds with the filler as well as with the polymer and thereby produce a good interaction between the filler surface and the polymer. They reduce the mixture viscosity and facilitate the dispersion of the filler during the mixing procedure.
Furthermore it is known that the use of commercially available silane coupling agents (DE 22 55 577) with three alkoxy substituents on the silicon atom leads to the release of considerable amounts of alcohol during and after the binding to the filler. Since as a rule trimethoxy-substituted and triethoxy-substituted silanes are used, the corresponding alcohols methanol and ethanol are released during the application (Berkemeier, D.; Hader, W.; Rinker, M.; Heiss, G. ‘Mixing of silica compounds from the viewpoint of a manufacturer of internal mixers’, Gummi, Fasern, Kunststoffe (2001), 54(1), 17-22).
It is also known that methoxy-substituted and ethoxy-substituted silanes are more hydrolysis-active than the corresponding long-chain alkoxy-substituted silanes (E. R. Pohl, F. D. Osterholtz J. Adhesion Sci. Technology 6(1) 1992, 127-149) and accordingly can bind more rapidly to the filler, which means that from the economic aspect it has not been possible up to now to dispense with the use of methoxy-substituted and ethoxy-substituted silanes.
Organosilicon compounds of the general formula [RO(R′O)2Si—R″]nXm and [R′O (RO)2Si—R″]nXm are known from DE 10163941.
A serious disadvantage in the use of known coupling agents based on alkoxysilanes is the release of stoichiometric amounts of volatile alcohols, such as for example methanol and ethanol, into the environment during and after the binding of the alkoxysilane to the filler.